Balance of Systems

Modular Trunk Cable with Self-Termination Construction

The trunk cabling portion of a microinverter system is extremely important since it directly impacts labor costs at an installation site. The Chilicon modular trunk and branch cabling system incorporates industry standard 10 AWG VNTC tray cable with a UV and cut resistant outer jacket. Each 'modular' component of the the 4 conductor cableplugs together right on the job site. For the first time, you can mix landscape and portrait mode PV module layouts side-by-side on the same string. In addition, the trunk cable is 'Self-Terminating' as shown in the figure below. There is no longer a need to procure 'termination caps' for the end of each microinverter string.

The trunk cable's 10 AWG cabling enables use of 30 A OCP devices (typically a 2 pole circuit breakers). This means that 20 CP250e devices running 289W output can be wired on a single 30 A string in 240V split phase mode, or 18 CP250e devices running 277W output can be wired on a single 30A string in 208V three phase mode.

In the case of the 720W output, CP-720 device, 8 inverters (16 modules) can be wired to a 30A breaker in 240V split phase mode, or 7 inverters (14 modules) in 208V three phase mode.

Click here for a more detailed Diagram of the modular trunk cable components and a self-terminating layout. Note that wiring for CP-720 twin inverters has special considerations. Examples of common configurations can be found in CP-720 Wiring Diagram Examples.

Integrated Grounding

Chilicon Power inverters feature Integrated (DC isolated) Ground. Because the DC circuit is isolated and insulated from ground, these microinverters do not require a Grounding Electrode Conductor (GEC) connected between each microinverter. This means you don’t need to attach a separate copper grounding conductor to each microinverter or worry about a continuous run to ground.

Electrical code requires two types of grounding conductors: the Grounding Electrode Conductor (GEC), which is used between the grounding electrode and the point where a normally current carrying conductor is intentionally bonded to ground and the Equipment Grounding Conductor (EGC), which grounds noncurrent carrying metal parts of the system, such as the racking and module frames. Because Chilicon Power microinverters have DC integrated (isolated) ground, they do not require a GEC. However electrical code still requires that exposed metal in the array be grounded (NEC 690.43 and 250.136(A)). This requirement is met for the microinverter because the ground conductor internal to the modular trunk cable acts as the EGC. It may be met for racking and modules with use of an EGC or WEEBs to provide bonding to this ground system.